Office: 6744 Science & Engineering Bldg
Phone: (615) 322-1461
Ph.D. University of California, Davis, 2010
B.A. Oberlin College, 2003
- Low Temperature Geochemistry
- Cave and Karst Studies
Jessica is interested in reconstructing the response of terrestrial hydroclimates to past climate change - including rapid climate transitions and long-term changes in mean climate. To do this, she develops records of isotopic and geochemical variability in terrestrial materials such as cave deposits (speleothems) and soil minerals. Speleothems and soil minerals capture the response of soil and groundwater to environmental changes on the surface, including changes in rainfall amount and source, temperature, and vegetation amount and type. These deposits are vital tools for investigating questions of global climate variability because they provide paleoclimate records in low and mid latitude terrestrial environments where other paleoclimate archives may be scarce. Jessica is also interested in understanding how modern cave systems respond to seasonal and interannual environmental changes with an eye toward using this understanding to provide an interpretative framework for calibrating paleoclimate records from cave deposits.
I am looking for motivated students to join my lab in Fall 2013!
Jessica's current research is focused on understanding how cave and soil minerals record environmental changes and using this knowledge to reconstruct past climate change. Current active areas of research include:
1) Jessica is conducting detailed multi-proxy studies of speleothems from caves in the central and northern Sierra Nevada of California, in collaboration with scientists at the University of California, Davis and the Berkeley Geochronology Center. Comparison of oxygen, carbon, and strontium isotope variations and elemental concentrations in speleothem calcite reveals complex interactions between local hydrologic changes and climatic variability across Northern California during the Pleistocene and Holocene. This team is also working closely with climate modelers at NCAR and the University of Wisconsin to investigate potential driving mechanisms of regional precipitation variability in western North America during the last deglaciation.
2) Jessica is working with scientists at the USGS, Western Kentucky University, and the Cave Research Foundation to investigate how modern cave environments in the Sierra Nevada and southern Kentucky respond to seasonal and interannual environmental variability, with the goal of using these observations to inform interpretations of speleothem geochemical records. The primary focus of this research is understanding how carbon cycles through soils and into cave waters and cave deposits using stable and radioactive carbon isotopes as tracers of these processes.
Figure at right from top to bottom: Summer and winter insolation at 38 °N, [Mg], [Sr] δ13C, and δ18O from a stalagmite from Moaning Cave, California compared to δ18O from the NGRIP ice core Greenland. This record describes changes in precipitation and temperature in California during the last deglaciation (Oster et al., 2009, 2012a).
Click on figure to enlarge.
What Students Do:
Jessica has exciting opportunities for students developing climate records from caves in the central Sierra Nevada, California as well as in modern cave environments in California and closer to Tennessee. Students will be able to work with multiple stable and radiogenic isotope systems and gain experience with geochrononology as well as the interpretation of paleoclimate proxy records. A new carbonate microsampler is on its way to Jessica's lab, so students will have the chance to work with this state of the art piece of equipment.
Masters student Christopher Myers is about to embark on an exciting new project developing U-series calibrated records of paleoseismicity from Indian speleothems. This project will be carried out in collaboration with Dr. Steven Goodbred at Vanderbilt as well as collaborators from ETH, Zürich.
Isotopes and Enviroment
Isotopes and Enviroment students in Vanderbilt University Hall, Mammoth Cave, Fall 2012.
Oster, J.L., Montanez, I.P., and Kelley, N.P., 2012. Response of a modern cave system to large seasonal precipitation variability. Geochimica et Cosmochimica Acta, v. 91, p. 92 – 108. doi:10.1016/j.gca.2012.05.027
Oster, J.L., Ibarra, D.L., Harris, C.H., and Maher, K. 2012. Influence of eolian deposition and rainfall amounts on the U-isotopic composition of soil water and soil minerals. Geochimica et Cosmochimica Acta, v. 88, p. 146 - 166. doi.org/10.1016/j.gca.2012.04.004
Oster, J.L., Montanez, I.P., Guilderson, T.P., Sharp, W.D. and Banner, J.L. 2010. Modeling speleothem δ13C variability in a central Sierra Nevada cave using 14C and 87Sr/86Sr, Geochimica et Cosmochimica Acta, v. 74, p. 5228 - 5242. doi:10.1016/j.gca.2010.06.030
Oster, J.L., Montanez, I.P., Sharp, W.D. and Cooper, K.M. 2009. Late Pleistocene California drought during deglaciation and Arctic Warming: Earth and Planetary Science Letters, v. 288, p. 434 – 443. doi:10.1016/j.epsl.2009.10.003